Optical module having multiple laser diode devices and a support member

ABSTRACT

A method and device for emitting electromagnetic radiation at high power using nonpolar or semipolar gallium containing substrates such as GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, is provided. In various embodiments, the laser device includes plural laser emitters emitting green or blue laser light, integrated a substrate.

This application is a continuation of U.S. application Ser. No.16/281,912, filed Feb. 21, 2019 which is a continuation of U.S.application Ser. No. 15/803,301, filed Nov. 3, 2017, which is acontinuation of U.S. application Ser. No. 15/159,595, filed May 19,2016, which is a continuation of U.S. application Ser. No. 14/684,240,filed on Apr. 10, 2015, which is a continuation of U.S. application Ser.No. 13/732,233, filed on Dec. 31, 2012, which is a continuation-in-partof U.S. application Ser. No. 13/356,355, filed on Jan. 23, 2012, whichclaims priority to U.S. Provisional Application 61/435,578, filed onJan. 24, 2011, the contents of which are hereby incorporated byreference for all purposes.

BACKGROUND OF THE INVENTION

In the late 1800's, Thomas Edison invented the light bulb. Theconventional light bulb, commonly called the “Edison bulb,” has beenused for over one hundred years for a variety of applications includinglighting and displays. The conventional light bulb uses a tungstenfilament enclosed in a glass bulb sealed in a base, which is screwedinto a socket. The socket is coupled to an AC power or DC power source.The conventional light bulb can be found commonly in houses, buildings,and outdoor lightings, and other areas requiring light or displays.Unfortunately, drawbacks exist with the conventional light bulb:

-   -   The conventional light bulb dissipates more than 90% of the        energy used as thermal energy.    -   The conventional light bulb routinely fails due to thermal        expansion and contraction of the filament element.    -   The conventional light bulb emits light over a broad spectrum,        much of which is not perceived by the human eye.    -   The conventional light bulb emits in all directions, which is        undesirable for applications requiring strong directionality or        focus, e.g. projection displays, optical data storage, etc.

In 1960, the laser was demonstrated by Theodore H. Maiman at HughesResearch Laboratories in Malibu. This laser utilized a solid-state flashlamp-pumped synthetic ruby crystal to produce red laser light at 694 nm.By 1964, blue and green laser output was demonstrated by William Bridgesat Hughes Aircraft utilizing a gas laser design called an Argon ionlaser. The Ar-ion laser utilized a noble gas as the active medium andproduce laser light output in the UV, blue, and green wavelengthsincluding 351 nm, 454.6 nm, 457.9 nm, 465.8 nm, 476.5 nm, 488.0 nm,496.5 nm, 501.7 nm, 514.5 nm, and 528.7 nm. The Ar-ion laser had thebenefit of producing highly directional and focusable light with anarrow spectral output, but the efficiency, size, weight, and cost ofthe lasers were undesirable.

As laser technology evolved, more efficient lamp pumped solid statelaser designs were developed for the red and infrared wavelengths, butthese technologies remained a challenge for blue and green and bluelasers. Lamp pumped solid-state lasers were developed in the infrared,and the output wavelength was converted to the visible using specialtycrystals with nonlinear optical properties. A green lamp pumpedsolid-state lasers had 3 stages: electricity powers lamp, lamp excitesgain crystal, which lases at 1064 nm, 1064 nm goes into frequencyconversion crystal, which converts, to visible 532 nm. The resultinggreen and blue lasers were called “lamp pumped solid state lasers withsecond harmonic generation” (LPSS with SHG) and were more efficient thanAr-ion gas lasers, but were still too inefficient, large, expensive,fragile for broad deployment outside of specialty scientific and medicalapplications. Additionally, the gain crystal used in the solid-statelasers typically had energy storage properties, which made the lasersdifficult to modulate at high speeds, which limited its broaderdeployment.

To improve the efficiency of these visible lasers, high power diode (orsemiconductor) lasers were utilized. These “diode pumped solid statelasers with SHG” (DPSS with SHG) had 3 stages: electricity powers 808 nmdiode laser, 808 nm excites gain crystal, which lases at 1064 nm, 1064nm goes into frequency conversion crystal, which converts, to visible532 nm. The DPSS laser technology extended the life and improved theefficiency of the LPSS lasers, and further commercialization ensue intomore high-end specialty industrial, medical, and scientificapplications. The change to diode pumping increased the system cost andrequired précised temperature controls, leaving the laser withsubstantial size, power consumption, while not addressing the energystorage properties which made the lasers difficult to modulate at highspeeds.

As high power laser diodes evolved and new specialty SHG crystals weredeveloped, it became possible to directly convert the output of theinfrared diode laser to produce blue and green laser light output. These“directly doubled diode lasers” or SHG diode lasers had 2 stages:electricity powers 1064 nm semiconductor laser, 1064 nm goes intofrequency conversion crystal which converts to visible 532 nm greenlight. These lasers designs are meant to improve the efficiency, costand size compared to DPSS-SHG lasers, but the specialty diodes andcrystals required make this challenging. Additionally, while thediode-SHG lasers have the benefit of being directly modulate-able, theysuffer from severe sensitivity to temperature which limits theirapplication.

High power direct diode lasers have been in existence for the past fewdecades, beginning with laser diodes based on the GaAs material system,then moving to the AlGaAsP and InP material systems. More recently, highpower lasers based on GaN operating in the short wavelength visibleregime have become of great interest. More specifically, laser diodesoperating in the violet, blue, and eventually green regimes areattracting attention due to their application in optical storage,display systems, and others. Currently, high power laser diodesoperating in these wavelength regimes are based on polar c-plane GaN.The conventional polar GaN based laser diodes have a number ofapplications, but unfortunately, the device performance is ofteninadequate.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method and device for emittingelectromagnetic radiation at high power using nonpolar or semipolargallium containing substrates such as GaN, AlN, InN, InGaN, AlGaN, andAlInGaN, and others. In various embodiments, a laser device comprisesnumber of laser emitters, which emit red, green, or blue electromagneticradiation, integrated onto a substrate or back member. Merely by way ofexample, the invention can be applied to applications such as whitelighting, multi-colored lighting, lighting for flat panels, medical,metrology, beam projectors and other displays, high intensity lamps,spectroscopy, entertainment, theater, music, and concerts, analysisfraud detection and/or authenticating, tools, water treatment, laserdazzlers, targeting, communications, transformations, transportations,leveling, curing and other chemical treatments, heating, cutting and/orablating, pumping other optical devices, other optoelectronic devicesand related applications, and source lighting and the like.

In a specific embodiment, the present invention provides an opticalmodule apparatus comprising a form factor characterized by a length, awidth, and a height. In an example, the height is characterized by adimension of less than 11 mm, and greater than 1 mm, although there maybe variations. The apparatus has a support member and a plurality ofgallium and nitrogen containing laser diode devices numbered from 1through N overlying the support member. Each of the laser device iscapable of an emission of a laser beam, where N is greater than 1. Theemission can comprise a blue emission ranging from 415-485 nm wavelengthand/or a green emission ranging from 500-560 nm wavelength. The supportmember is configured to transport thermal energy from the plurality oflaser diode devices to a heat sink. The apparatus has a free space witha non-guided characteristic capable of transmitting the emission of eachof the laser beams from a plurality of laser beams. A combiner isconfigured to receive a plurality of laser beams of N incoming laserbeams from the plurality of gallium and nitrogen containing laser diodedevices. The combiner functions to cause an output beam with a selectedwavelength range, a spectral width, a power, and a spatialconfiguration, where N is greater than 1. In an example, the combinerconsists of free-space optics to create one or more free space opticalbeams. At least one of the incoming beams is characterized by apolarization purity of greater than 60% and less than 100%. As usedherein, the term “polarization purity” means greater than 50% of theemitted electromagnetic radiation is in a substantially similarpolarization state such as the transverse electric (TE) or transversemagnetic (TM) polarization states, but can have other meaningsconsistent with ordinary meaning. In an example, an operating opticaloutput power of at least 5 W to 200 W, characterizes the output beamfrom the plurality of laser beams. The apparatus also has an electricalinput interface configured to couple electrical input power to theplurality of laser diode devices and a thermal impedance of less than 4degrees Celsius per electrical watt of electrical input powercharacterizing a thermal path from the laser device to a heat sink. Theapparatus has an optical output power degradation of less than 20% in500 hours when operated within the output power range with a constantinput current at a base temperature of 25 degrees Celsius.

In an alternative specific embodiment, the present invention provides anoptical module apparatus. The apparatus has a form factor characterizedby a length, a width, and a height. In an example, the height ischaracterized by a dimension of less than 11 mm and greater than 1 mm,although there may be variations. In a specific embodiment, theapparatus has a support member and a plurality of gallium and nitrogencontaining laser diode devices numbered from 1 through N overlying thesupport member. Each of the laser device is capable of an emission of alaser beam, where N is greater than 1. The emission comprises a blueemission ranging from 415 nm to 485 nm wavelength and/or a greenemission ranging from 500 nm to 560 nm wavelength. The support member isconfigured to transport thermal energy from the plurality of laser diodedevices to a heat sink. The apparatus has a combiner configured toreceive a plurality of laser beams of N incoming laser beams. Theapparatus has at least one of the incoming beams characterized by apolarization purity of greater than 60% and less than 100% althoughthere can be variations. The apparatus has a predetermined ratedoperating optical output power range including at least 5 W and greater.The apparatus has an electrical input interface configured to coupleelectrical power to the plurality of laser diode devices and a thermalimpedance of less than 4 degrees Celsius per electrical watt of inputpower characterizing a thermal path from the laser device to a heatsink.

In yet an alternative embodiment, the present invention provides anoptical module apparatus. The apparatus has a form factor characterizedby a length, a width, and a height. In an example, the height ischaracterized by a dimension of less than 11 mm and greater than 1 mm,although there may be variations. The apparatus has a support member anda plurality of gallium and nitrogen containing laser diode devicesnumbered from 1 through N overlying the support member. Each of thelaser device is capable of an emission of a laser beam, where N isgreater than 1. The emission comprises a blue emission ranging from 415nm to 485 nm wavelength and/or a green emission ranging from 500 nm to560 nm wavelength. Each of the gallium and nitrogen containing laserdiodes is characterized by a nonpolar or a semipolar oriented surfaceregion. In an example, the apparatus has a laser stripe region overlyingthe nonpolar or semipolar surface region. Each of the laser striperegions is oriented in a c-direction or a projection of a c-direction.In an example, the laser stripe region is characterized by a first endand a second end. The support member is configured to transport thermalenergy from the plurality of laser diode devices to a heat sink. Theapparatus has a combiner configured to receive a plurality of laserbeams of N incoming laser beams. The combiner functions to cause anoutput beam with a selected wavelength range, spectral width, power, andspatial configuration, where N is greater than 1. The apparatus has atleast one of the incoming beams characterized by a polarization purityof greater than 60% up to 100% although there may be variations. In anexample, the optical module apparatus has a predetermined ratedoperating optical output power range including at least 5 W and greater.The apparatus has an electrical input interface configured to coupleelectrical power to the plurality of laser diode devices. A thermalimpedance of less than 4 degrees Celsius per electrical watt of inputpower characterizes a thermal path from the laser device to a heat sink.

In an example, the nonpolar or semipolar oriented surface region is asemipolar orientation characterized by the {20-21} or {20-2-1} plane, oralternatively, the nonpolar or semipolar oriented surface region is asemipolar orientation characterized by the {30-31} or {30-3-1} plane.Each of these planes may be slightly or substantially off cut dependingupon the embodiment. In an example, the nonpolar or semipolar orientedsurface region is a nonpolar orientation characterized by m-plane. In anexample, each of the laser devices is operable in an environmentcomprising at least 150,000 parts per-million (ppm) oxygen gas. Each ofthe laser device is substantially free from efficiency degradation overa time period from the oxygen gas. In an example, each of the laserdevices comprises a front facet and a rear facet.

Additional benefits are achieved over pre-existing techniques using thepresent invention. In particular, the present invention enables acost-effective optical device for laser applications, including laserbar for projectors, and the like. In a specific embodiment, the presentoptical device can be manufactured in a relatively simple and costeffective manner. Depending upon the embodiment, the present apparatusand method can be manufactured using conventional materials and/ormethods according to one of ordinary skill in the art. The present laserdevice uses a nonpolar or semipolar gallium nitride material capable ofachieving a violet or blue or green emission, among others. In one ormore embodiments, the laser device is capable of emitting longwavelengths such as those ranging from about 430 nm to 470 nm for theblue wavelength region or 500 nm to about 540 nm for the greenwavelength region, but can be others such as the violet region. Ofcourse, there can be other variations, modifications, and alternatives.Depending upon the embodiment, one or more of these benefits may beachieved. These and other benefits may be described throughout thepresent specification and more particularly below.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the latter portions of thespecification and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram illustrating an optical device accordingto an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a laser device according to anembodiment of the present invention.

FIG. 3 is a simplified diagram illustrating a laser device having aplurality of emitters according to an embodiment of the presentinvention.

FIG. 4 is a simplified diagram illustrating a front view of a laserdevice with multiple cavity members according to an embodiment of thepresent invention.

FIGS. 5A and 5B are diagrams illustrating a laser package having“p-side” facing up according to an embodiment of the present invention.

FIGS. 6A and 6B are simplified diagram illustrating a laser packagehaving “p-side” facing down according to an embodiment of the presentinvention.

FIG. 7 is a simplified diagram illustrating an individually addressablelaser package according to an embodiment of the present invention.

FIG. 8 is a simplified diagram illustrating a laser bar having apatterned bonding substrate according to an embodiment of the presentinvention.

FIG. 9 is a simplified diagram illustrating a plurality of laser barsconfigured with optical combiners according to embodiments of thepresent invention.

FIG. 10 is a schematic of laser module with a fibered array according toan example of the present invention.

FIG. 11 is a schematic of laser module with a fiber bundle according toan example of the present invention.

FIG. 12 is a schematic of laser module with lensed fibers according toan example of the present invention.

FIG. 13 is a schematic of a free space laser combiner according to anexample of the present invention.

FIG. 14 is a schematic of a free space mirror based laser combineraccording to an example of the present invention.

FIG. 15 is a schematic of an enclosed free space laser module accordingto an example of the present invention.

FIG. 16 is an illustration on strong lifetime dependence on lasercoupling schemes according to an example of the present invention.

FIG. 17 is a simplified illustration of module form factor according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Optical module devices that combine the light output from multiple laserchips and/or laser bars and couple the light into a common fiber ormedium are well established in the red and infrared wavelength regimes.Such module devices serve applications where very high powers (>10 Wto >100 W) and/or very high brightness are required or where a remotelight source can serve an increased functionality. Laser diodes based onGaN that emit in the blue and green wavelength regime have seenimprovements in efficiency, power, and lifetime over the years. Opticalmodule devices leveraging these high performance blue and greenGaN-based lasers are sure to emerge as key light sources providinggreater than 5 W to greater than 50 W or 100 W or 200 W of opticaloutput power in existing and emerging applications where high brightnessor remote sources of blue and/or green light are needed. Suchapplications include high brightness displays, specialty lighting,medical devices, defense systems, and others.

A popular and efficient way to combine the light from the emitterswithin the module is by direct fiber coupling. In this configuration thelaser chips or bars would be mounted onto a carrier and the emittedlight would be coupled into a fiber by either using a close optic suchas fast axis collimating (FAC) lens first then the fiber, or directlyusing a fiber with a shaped lens formed at the end facing the laser. Ineither case the fiber is positioned close to the laser facet. Typicalfiber dimensions ranges from 100 μm to 800 μm, and with a NA of 0.18 orgreater. In these configurations the fibers are usually in closevicinity to the laser diode facet region, which are well-known for theirsensitivity to optical or other damage mechanisms. Typical distances ofthe optical fiber from the laser diode facet would be about 0.2 mm toabout 10 mm. Although this a proven method for combining the opticaloutputs from red or infrared laser diodes, drawbacks could exist whenfiber coupling blue or green devices based on conventional c-plane basedGaN lasers. One such drawback is reduced lifetime and rapid degradationof the optical output from the module. Such reliability issues couldresult from specific light behaviors due to close proximity of opticalsurfaces and especially fiber end to the emitting facet of the laser.These and other drawbacks have been overcome with the present method anddevices, which are described throughout the present specification andmore particularly below.

The present invention provides high power GaN-based laser devices andrelated methods for making and using these laser devices. Specifically,laser devices are configured to operate with 0.5 W to 5 W or 5 W to 20 Wor 20 W to 100 W or 200 W, or greater of output power in the blue orgreen wavelength regimes. The laser devices are manufactured from bulknonpolar or semipolar gallium and nitrogen containing substrates. Asmentioned above, the output wavelength of the laser devices can be inthe blue wavelength region of 425 nm to 475 nm and the green wavelengthregion 500 nm to 545 nm. Laser devices according to embodiments of thepresent invention can also operate in wavelengths such as violet (395 nmto 425 nm) and blue-green (475 nm to 505 nm). The laser devices can beused in various applications, such as projection system where a highpower laser is used to project video content.

FIG. 1 is a simplified diagram illustrating an optical device. As anexample, the optical device includes a gallium nitride substrate member101 having a crystalline surface region characterized by a semipolar ornonpolar orientation. For example, the gallium nitride substrate memberis a bulk GaN substrate characterized by having a nonpolar or semipolarcrystalline surface region, but can be others. The bulk GaN substratemay have a surface dislocation density below 10⁵ cm′ or 10⁵ to 10⁷ cm′.The nitride crystal or wafer may comprise Al_(x)In_(y)Ga_(1-x-y)N, where0≤x, y, x+y≤1. In one specific embodiment, the nitride crystal comprisesGaN. In one or more embodiments, the GaN substrate has threadingdislocations, at a concentration between about 10⁵ cm′ and about 10⁸cm′, in a direction that is substantially orthogonal or oblique withrespect to the surface. In various embodiments, the GaN substrate ischaracterized by a nonpolar orientation (e.g., m-plane), wherewaveguides are oriented in the c-direction or substantially orthogonalto the a-direction.

In certain embodiments, GaN surface orientation is substantially in the{20-21} orientation, and the device has a laser stripe region formedoverlying a portion of the off-cut crystalline orientation surfaceregion. For example, the laser stripe region is characterized by acavity orientation substantially in a projection of a c-direction, whichis substantially normal to an a-direction. In a specific embodiment, thelaser strip region has a first end 107 and a second end 109. In apreferred embodiment, the device is formed on a projection of ac-direction on a {20-21} gallium and nitrogen containing substratehaving a pair of cleaved mirror structures, which face each other.

In a preferred embodiment, the device has a first cleaved facet providedon the first end of the laser stripe region and a second cleaved facetprovided on the second end of the laser stripe region. In one or moreembodiments, the first cleaved is substantially parallel with the secondcleaved facet. Mirror surfaces are formed on each of the cleavedsurfaces. The first cleaved facet comprises a first mirror surface. In apreferred embodiment, the first mirror surface is provided by a top-sideskip-scribe scribing and breaking process. The scribing process can useany suitable techniques, such as a diamond scribe or laser scribe orcombinations. In a specific embodiment, the first mirror surfacecomprises a reflective coating. The reflective coating is selected fromsilicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia,including combinations, and the like. The first mirror surface can alsohave an anti-reflective coating.

Also in a preferred embodiment, the second cleaved facet comprises asecond mirror surface. The second mirror surface is provided by a topside skip-scribe scribing and breaking process according to a specificembodiment. Preferably, the scribing is diamond scribed or laser scribedor the like. In a specific embodiment, the second mirror surfacecomprises a reflective coating, such as silicon dioxide, hafnia, andtitania, tantalum pentoxide, zirconia, combinations, and the like. In aspecific embodiment, the second mirror surface has an anti-reflectivecoating.

In a specific embodiment on a nonpolar Ga-containing substrate, thedevice is characterized by a spontaneously emitted light is polarized insubstantially perpendicular to the c-direction. In a preferredembodiment, the spontaneously emitted light is characterized by apolarization ratio of greater than 0.1 to about 1 perpendicular to thec-direction. In a preferred embodiment, the spontaneously emitted lightcharacterized by a wavelength ranging from about 430 nanometers to about470 nm to yield a blue emission, or about 500 nanometers to about 540nanometers to yield a green emission, and others. For example, thespontaneously emitted light can be violet (e.g., 395 to 420 nanometers),blue (e.g., 430 to 470 nm); green (e.g., 500 to 540 nm), or others. In apreferred embodiment, the spontaneously emitted light is highlypolarized and is characterized by a polarization ratio of greater than0.4. In another specific embodiment on a semipolar {20-21} Ga-containingsubstrate, the device is also characterized by a spontaneously emittedlight is polarized in substantially parallel to the a-direction orperpendicular to the cavity direction, which is oriented in theprojection of the c-direction.

In a specific embodiment, the present invention provides an alternativedevice structure capable of emitting 501 nm and greater light in a ridgelaser embodiment. The device is provided with one or more of thefollowing epitaxially grown elements:

an n-GaN cladding layer with a thickness from 100 nm to 3000 nm with Sidoping level of 5E17 cm⁻³ to 3E18 cm⁻³;

an n-side SCH layer comprised of InGaN with molar fraction of indium ofbetween 2% and 10% and thickness from 20 nm to 200 nm;

multiple quantum well active region layers comprised of at least two 2.0nm to 8.5 nm InGaN quantum wells separated by 1.5 nm and greater, andoptionally up to about 12 nm, GaN or InGaN barriers;

a p-side SCH layer comprised of InGaN with molar a fraction of indium ofbetween 1% and 10% and a thickness from 15 nm to 100 nm or an upperGaN-guide layer;

an electron blocking layer comprised of AlGaN with molar fraction ofaluminum of between 6% and 22% and thickness from 5 nm to 20 nm anddoped with Mg;

a p-GaN cladding layer with a thickness from 400 nm to 1000 nm with Mgdoping level of 2E17 cm⁻³ to 2E19 cm−3; and

a p++-GaN contact layer with a thickness from 20 nm to 40 nm with Mgdoping level of 1E19 cm⁻³ to 1E21 cm⁻³.

FIG. 2 is a cross-sectional view of a laser device 200. As shown, thelaser device includes gallium nitride substrate 203, which has anunderlying n-type metal back contact region 201. For example, thesubstrate 203 may be characterized by a semipolar or nonpolarorientation. The device also has an overlying n-type gallium nitridelayer 205, an active region 207, and an overlying p-type gallium nitridelayer structured as a laser stripe region 209. Each of these regions isformed using at least an epitaxial deposition technique of metal organicchemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), orother epitaxial growth techniques suitable for GaN growth. The epitaxiallayer is a high quality epitaxial layer overlying the n-type galliumnitride layer. In some embodiments the high quality layer is doped, forexample, with Si or O to form n-type material, with a dopantconcentration between about 10¹⁶ cm⁻³ and 10²⁰ cm⁻³.

An n-type Al_(u)In_(v)Ga_(1-u-v)N layer, where 0≤u, v, u+v≤1, isdeposited on the substrate. The carrier concentration may lie in therange between about 10¹⁶ cm⁻³ and 10²⁰ cm⁻³. The deposition may beperformed using metalorganic chemical vapor deposition (MOCVD) ormolecular beam epitaxy (MBE).

For example, the bulk GaN substrate is placed on a susceptor in an MOCVDreactor. After closing, evacuating, and back-filling the reactor (orusing a load lock configuration) to atmospheric pressure, the susceptoris heated to a temperature between about 1000 and about 1200 degreesCelsius in the presence of a nitrogen-containing gas. The susceptor isheated to approximately 900 to 1200 degrees Celsius under flowingammonia. A flow of a gallium-containing metalorganic precursor, such astrimethylgallium (TMG) or triethylgallium (TEG) is initiated, in acarrier gas, at a total rate between approximately 1 and 50 standardcubic centimeters per minute (sccm). The carrier gas may comprisehydrogen, helium, nitrogen, or argon. The ratio of the flow rate of thegroup V precursor (ammonia) to that of the group III precursor(trimethylgallium, triethylgallium, trimethylindium, trimethylaluminum)during growth is between about 2000 and about 12000. A flow of disilanein a carrier gas, with a total flow rate of between about 0.1 sccm and10 sccm, is initiated.

In one embodiment, the laser stripe region is p-type gallium nitridelayer 209. The laser stripe is provided by a dry etching process, butwet etching can be used. The dry etching process is an inductivelycoupled process using chlorine bearing species or a reactive ion etchingprocess using similar chemistries. The chlorine bearing species arecommonly derived from chlorine gas or the like. The device also has anoverlying dielectric region, which exposes 213 contact region. Thedielectric region is an oxide such as silicon dioxide or siliconnitride, and a contact region is coupled to an overlying metal layer215. The overlying metal layer is preferably a multilayered structurecontaining gold and platinum (Pt/Au), palladium and gold (Pd/Au), ornickel gold (Ni/Au).

Active region 207 preferably includes one to ten quantum well regions ora double heterostructure region for light emission. Following depositionof the n-type Al_(u)In_(v)Ga_(1-u-v)N layer to achieve a desiredthickness, an active layer is deposited. The quantum wells arepreferably InGaN with GaN, AlGaN, InAlGaN, or InGaN barrier layersseparating them. In other embodiments, the well layers and barrierlayers comprise Al_(w)In_(x)Ga_(1-w-x)N and Al_(y)In_(z)Ga_(1-y-z)N,respectively, where 0≤w, x, y, z, w+x, y+z≤1, where w<u, y and/or x>v, zso that the bandgap of the well layer(s) is less than that of thebarrier layer(s) and the n-type layer. The well layers and barrierlayers each have a thickness between about 1 nm and about 20 nm. Thecomposition and structure of the active layer are chosen to providelight emission at a preselected wavelength. The active layer may be leftundoped (or unintentionally doped) or may be doped n-type or p-type.

The active region can also include an electron blocking region, and aseparate confinement heterostructure. The electron-blocking layer maycomprise Al_(s)In_(t)Ga_(1-s-t)N, where 0≤s, t, s+t≤1, with a higherbandgap than the active layer, and may be doped p-type. In one specificembodiment, the electron blocking layer includes AlGaN. In anotherembodiment, the electron blocking layer includes an AlGaN/GaNsuper-lattice structure, comprising alternating layers of AlGaN and GaN,each with a thickness between about 0.2 nm and about 5 nm.

As noted, the p-type gallium nitride structure is deposited above theelectron blocking layer and active layer(s). The p-type layer may bedoped with Mg, to a level between about 10¹⁶ cm⁻³ and 10²² cm⁻³, with athickness between about 5 nm and about 1000 nm. The outermost 1-50 nm ofthe p-type layer may be doped more heavily than the rest of the layer,so as to enable an improved electrical contact. The device also has anoverlying dielectric region, for example, silicon dioxide, which exposes213 contact region.

The metal contact is made of suitable material such as silver, gold,aluminum, nickel, platinum, rhodium, palladium, chromium, or the like.The contact may be deposited by thermal evaporation, electron beamevaporation, electroplating, sputtering, or another suitable technique.In a preferred embodiment, the electrical contact serves as a p-typeelectrode for the optical device. In another embodiment, the electricalcontact serves as an n-type electrode for the optical device. The laserdevices illustrated in FIGS. 1 and 2 and described above are typicallysuitable for relative low-power applications.

In various embodiments, the present invention realizes high output powerfrom a diode laser is by widening one or more portions of the lasercavity member from the single lateral mode regime of 1.0-3.0 μm to themulti-lateral mode range 5.0-20 μm. In some cases, laser diodes havingcavities at a width of 50 μm or greater are employed.

The laser stripe length, or cavity length ranges from 300 to 3000 μm andemploys growth and fabrication techniques such as those described inU.S. patent application Ser. No. 12/759,273, filed Apr. 13, 2010, whichis incorporated by reference herein. As an example, laser diodes arefabricated on nonpolar or semipolar gallium containing substrates, wherethe internal electric fields are substantially eliminated or mitigatedrelative to polar c-plane oriented devices. It is to be appreciated thatreduction in internal fields often enables more efficient radiativerecombination. Further, the heavy hole mass is expected to be lighter onnonpolar and semipolar substrates, such that better gain properties fromthe lasers can be achieved.

One difficulty with fabricating high-power GaN-based lasers with widecavity designs is a phenomenon where the optical field profile in thelateral direction of the cavity becomes asymmetric where there are localbright regions and local dim regions. Such behavior is often referred toas filamenting and can be induced by lateral variations in the index ofrefraction or thermal profile, which alters the mode guidingcharacteristics. Such behavior can also be a result of non-uniformitiesin the local gain/loss caused by non-uniform injection of carriers intothe active region or current crowding where current is preferentiallyconducted through the outer regions of the laser cavity. That is, thecurrent injected through the p-side electrode tends towards the edge ofthe etched p-cladding ridge/stripe required for lateral waveguiding, andthen conducted downward where the holes recombine with electronsprimarily near the side of the stripe. Regardless of the cause, suchfilamenting or non-symmetric optical field profiles can lead to degradedlaser performance as the stripe width is increased.

FIG. 3 is a simplified diagram illustrating a laser device having aplurality of emitters according to an embodiment of the presentinvention. As shown in FIG. 3 , a laser device includes a substrate anda plurality of emitters. Each cavity member, in conjunction with theunderlying active region within the substrate and other electricalcomponents, is a part of a laser diode. The laser device in FIG. 3includes three laser diodes, each having its emitter or cavity member(e.g., cavity member 302 functions a waveguide of a laser diode) andsharing the substrate 301, which contains one or more active regions. Invarious embodiments, the active regions include quantum wells or adouble heterostructure for light emission. The cavity members functionas waveguides. A device with multiple cavity members integrated on asingle substrate and the method of manufacturing thereof are describedin the U.S. Provisional Patent Application No. 61/345,561, filed May 17,2010, which is hereby incorporated by reference.

The substrate shown in FIG. 3 contains gallium and nitrogen materialfabricated from nonpolar or semipolar bulk GaN substrate. The cavitymembers as shown are arranged in parallel to one another. For example,cavity member 301 includes a front mirror and a back mirror, similar tothe cavity member 101 illustrated in FIG. 1 . Each of the laser cavitiesis characterized by a cavity width, w, ranging from about 1 to about 6μm. Such arrangement of cavity members increases the effective stripewidth while assuring that the cavity members are uniformly pumped. In anembodiment, cavity members are characterized by a substantially equallength and width.

Depending on the application, a high power laser device can have anumber of cavity members. The number of cavity members, n, can rangefrom 2 to 5, 10, or even 20. The lateral spacing, or the distanceseparating one cavity member from another, can range from 2 μm to 25 μm,depending upon the requirements of the laser diode. In variousembodiments, the length of the cavity members can range from 300 μm to2000 μm, and in some cases as much as 3000 μm.

In a preferred embodiment, laser emitters (e.g., cavity members asshown) are arranged as a linear array on a single chip to emit blue orgreen laser light. The emitters are substantially parallel to oneanother, and they can be separated by 3 μm to 15 μm, by 15 μm to 75 μm,by 75 μm to 150 μm, or by 150 μm to 300 μm. The number of emitters inthe array can vary from 3 to 15 or from 15 to 30, from 30 to 50, or from50 to 100, or more than 100. Each emitter may produce an average outputpower of 25 to 50 mW, 50 to 100 mW, 100 to 250 mW, 250 to 500 mW, 500 to1000 mW, or greater than 1 W. Thus the total output power of the laserdevice having multiple emitters can range from 200 to 500 mW, 500 to1000 mW, 1-2 W, 2-5 W, 5-10 W, 10-20 W, and greater than 20 W.

With current technology, the dimension of the individual emitters wouldbe widths of 1.0 to 3.0 μm, 3.0 to 6.0 μm, 6.0 to 10.0 μm, 10 to 20.0μm, 20 to 30 μm, and greater than 30 μm. The lengths range from 400 μmto 800 μm, 800 μm to 1200 μm, 1200 μm to 1600 μm, or greater than 1600μm.

The cavity member has a front end and a back end. The laser device isconfigured to emit laser beam through the front mirror at the front end.The front end can have anti-reflective coating or no coating at all,thereby allowing radiation to pass through the mirror without excessivereflectivity. Since no laser beam is to be emitted from the back end ofthe cavity member, the back mirror is configured to reflect theradiation back into the cavity. For example, the back mirror includeshighly reflective coating with a reflectivity greater than 85% or 95%.

FIG. 4 is a simplified diagram illustrating a front view of a laserdevice with multiple cavity members. As shown in FIG. 4 , an activeregion 307 can be seen as positioned in the substrate 301. The cavitymember 302 as shown includes a via 306. Vias are provided on the cavitymembers and opened in a dielectric layer 303, such as silicon dioxide.The top of the cavity members with vias can be seen as laser ridges,which expose electrode 304 for an electrical contact. The electrode 304includes p-type electrode. In a specific embodiment, a common p-typeelectrode is deposited over the cavity members and dielectric layer 303,as illustrated in FIG. 4 .

The cavity members are electrically coupled to each other by theelectrode 304. The laser diodes, each having an electrical contactthrough its cavity member, share a common n-side electrode. Depending onthe application, the n-side electrode can be electrically coupled to thecavity members in different configurations. In a preferred embodiment,the common n-side electrode is electrically coupled to the bottom sideof the substrate. In certain embodiments, n-contact is on the top of thesubstrate, and the connection is formed by etching deep down into thesubstrate from the top and then depositing metal contacts. For example,laser diodes are electrically coupled to one another in a parallelconfiguration. In this configuration, when current is applied to theelectrodes, all laser cavities can be pumped relatively equally.Further, since the ridge widths will be relatively narrow in the 1.0 to5.0 μm range, the center of the cavity member will be in close vicinityto the edges of the ridge (e.g., via) such that current crowding ornon-uniform injection will be mitigated. Most importantly, filamentingcan be prevented and the lateral optical field profile can be symmetricin such narrow cavities as shown in FIG. 2A.

It is to be appreciated that the laser device with multiple cavitymembers has an effective ridge width of n×w, which could easily approachthe width of conventional high power lasers having a width in the 10 to50 μm range. Typical lengths of this multi-stripe laser could range from400 μm to 2000 μm, but could be as much as 3000 μm. A schematicillustration of a conventional single stripe narrow ridge emitterintended for lower power applications of 5 to 500 mW is shown in FIG. 1with the resulting laterally symmetric field profile in FIG. 2A. Aschematic diagram of a multi-stripe emitter as an example thisembodiment intended for operation powers of 0.5 to 10 W is shown in FIG.2 .

The laser device illustrated in FIGS. 3 and 4 has a wide range ofapplications. For example, the laser device can be coupled to a powersource and operate at a power level of 0.5 to 10 W. In certainapplications, the power source is specifically configured to operate ata power level of greater than 10 W. The operating voltage of the laserdevice can be less than 5 V, 5.5 V, 6 V, 6.5 V, 7 V, and other voltages.In various embodiments, the wall plug efficiency (e.g., totalelectrical-to-optical power efficiency) can be 15% or greater, 20% orgreater, 25% or greater, 30% or greater, 35% or greater.

A typical application of laser devices is to emit a single ray of laserlight. As the laser device includes a number of emitters, an opticalmember is needed to combine or collimate output from the emitters. FIGS.5A and 5B are diagrams illustrating a laser package having “p-side”facing up. As shown in FIG. 5A, a laser bar is mounted on a submount.The laser bar includes an array of emitters (e.g., as illustrated inFIGS. 3 and 4 ). The laser bar is attached the submount, which ispositioned between the laser bar and a heat sink. It is to beappreciated that the submount allows the laser bar (e.g., galliumnitride material) to securely attached to the heat sink (e.g., coppermaterial with high thermal emissivity). In various embodiments, submountincludes aluminum nitride material characterized by a high thermalconductivity. For example, thermal conductivity for aluminum nitridematerial used in the submount can exceed 200 W/(mk). Other types ofmaterials can be used for submount as well, such as diamond, coppertungsten alloy, beryllium oxide. In a preferred embodiment, the submountmaterials are used to compensate coefficient of thermal expansion (CTE)mismatch between the laser bar and the heat sink.

In FIG. 5A, the “p-side” (i.e., the side with emitters) of the laser barfaces upward and thus is not electrically coupled to the submount. Thep-side of the laser bar is electrically coupled to the anode of a powersource through a number of bonding wires. Since both the submount andthe heat sink are conductive, the cathode electrode of the power sourcecan be electrically coupled to the other side of the laser bar throughthe submount and the heat sink.

In a preferred embodiment, the array of emitters of the laser bar ismanufactured from a gallium nitride substrate. The substrate can havesurface characterized by a semi-polar or non-polar orientation. Thegallium nitride material allows the laser device to be packaged withouthermetic sealing. More specifically, by using the gallium nitridematerial, the laser bar is substantially free from AlGaN or InAlGaNcladdings. When the emitter is substantially in proximity to p-typematerial, the laser device is substantially free from p-type AlGaN orp-type InAlGaN material. Typically, AlGaN or InAlGaN claddings areunstable when operating in normal atmosphere, as they interact withoxygen. To address this problem, conventional laser devices comprisingAlGaN or InAlGaN material are hermetically sealed to prevent interactionbetween AlGaN or InAlGaN and air. In contrast, since AlGaN or InAlGaNcladdings are not present in laser devices according to embodiments ofthe present invention, the laser devices does not need to behermetically packaged. The cost of manufacturing laser devices andpackages according to embodiments of the present invention can be lowerthan that of conventional laser devices by eliminating the need forhermetic packaging.

FIG. 5B is a side view diagram of the laser device illustrated in FIG.5A. The laser bar is mounted on the submount, and the submount ismounted on the heat side. As explained above, since the laser barincludes a number of emitters, a collimating lens is used to combine theemitted laser to form a desired laser beam. In a preferred embodiment,the collimating lens is a fast-axis collimating (FAC) lens that ischaracterized by a cylindrical shape.

FIGS. 6A and 6B are simplified diagram illustrating a laser packagehaving “p-side” facing down according to an embodiment of the presentinvention. In FIG. 6A, a laser bar is mounted on a submount. The laserbar includes an array of emitters (e.g., as illustrated in FIGS. 3 and 4). In a preferred embodiment, the laser bar includes substratecharacterized by a semipolar or non-polar orientation. The laser bar isattached the submount, which is positioned between the laser bar and aheat sink. The “p-side” (i.e., the side with emitters) of the laser barfaces downed and thus is directly coupled to the submount. The p-side ofthe laser bar is electrically coupled to the anode of a power sourcethrough the submount and/or the heat sink. The other side of the laserbar is electrically coupled to the cathode of the power source through anumber of bonding wires.

FIG. 6B is a side view diagram of the laser device illustrated in FIG.6A. As shown, the laser bar is mounted on the submount, and the submountis mounted on the heat side. As explained above, since the laser barincludes a number of emitters, a collimating lens is used to combine theemitted laser to form a desired laser beam. In a preferred embodiment,the collimating lens is a fast-axis collimating (FAC) lens that ischaracterized by a cylindrical shape.

FIG. 7 is a simplified diagram illustrating an individually addressablelaser package according to an embodiment of the present invention. Thelaser bar includes a number of emitters separated by ridge structures.Each of the emitter is characterized by a width of about 90-200 μm, butit is to be understood that other dimensions are possible as well. Eachof the laser emitters includes a pad for p-contact wire bond. Forexample, electrodes can be individually coupled to the emitters so thatit is possible to selectively turning a emitter on and off. Theindividually addressable configuration shown in FIG. 7 provides numerousbenefits. For example, if a laser bar having multiple emitters is notindividually addressable, laser bar yield during manufacturing can be aproblem, since many individual laser devices need to be good in orderfor the bar to pass, and that means laser bar yield will be lower thanindividual emitter yield. In addition, setting up the laser bar withsingle emitter addressability makes it possible to screen each emitter.In a certain embodiments, a control module is electrically coupled tothe laser for individually controlling devices of the laser bar.

FIG. 8 is a simplified diagram illustrating a laser bar having apatterned bonding substrate according to an embodiment of the presentinvention. As shown, laser devices are characterized by a width ofaround 30 μm. Depending on the application, other widths are possible aswell. Laser emitters having pitches smaller than about 90 microns aredifficult to form wire bonds. In various embodiments, a patternedbonding substrate is used for forming contacts. For example, the patternbonding substrates allows for the width to be as low as 10-30 μm.

FIG. 9 is a simplified diagram illustrating laser bars configured withan optical combiner according to embodiments of the present invention.As shown, the diagram includes a package or enclosure for multipleemitters. Each of the devices is configured on a single ceramic ormultiple chips on a ceramic, which are disposed on common heatsink. Asshown, the package includes all free optics coupling, collimators,mirrors, spatially or polarization multiplexed for free space output orrefocused in a fiber or other waveguide medium. As an example, thepackage has a low profile and may include a flat pack ceramic multilayeror single layer. The layer may include a copper, a copper tungsten basesuch as butterfly package or covered CT mount, Q-mount, or others. In aspecific embodiment, the laser devices are soldered on CTE matchedmaterial with low thermal resistance (e.g., AlN, diamond, diamondcompound) and forms a sub-assembled chip on ceramics. The sub-assembledchip is then assembled together on a second material with low thermalresistance such as copper including, for example, active cooling (i.e.,simple water channels or micro channels), or forming directly the baseof the package equipped with all connections such as pins. The flatpackis equipped with an optical interface such as window, free space optics,connector or fiber to guide the light generated and a coverenvironmentally protective.

FIG. 10 is an example of laser module coupled to a fiber array. Eachemitter from the laser bar is individually coupled into the fiber arraythrough fast axis collimation (FAC) lens. In such a configuration thefiber is in the vicinity of the laser diode chip, typically within 0.2to 10 mm.

FIG. 11 is an example of laser module with a fiber bundle. Aftercollimation by the fast axis collimation (FAC) lens and fiber coupling,the fibers are bundled together at the end. In such a configuration thefiber is in the vicinity of the laser diode chip, typically within 0.5to 10 mm.

FIG. 12 is an example of laser module with lensed fibers. In thisconfiguration lensed fibers are used for direct coupling to the laserdiode without the inclusion of a fast axis collimating (FAC) lens. Insuch a configuration the fiber is in the vicinity of the laser diodechip, typically within 0.2 to 2 mm.

In an example, the present invention provides an alternative opticalcoupling technique to combine the optical outputs from the individualemitters or laser bars within the optical module. By using free-spaceoptics to combine all of the optical outputs into one or multiplefree-space laser beams first, and then coupling the free space laserbeam(s) directly to the application, or to an optical fiber which wouldthen be coupled to the application, the degradation mechanism associatedwith direct fiber coupling would be avoided. In this configuration theoptical fiber is positioned in a remote location (10 to 100 mm) relativeto the laser diode facet region. As a result, the free-space couplingoptical module emitting blue or green light could possess a longlifetime for reliable operation.

FIG. 13 is an example of a free space laser combiner. In thisconfiguration the emitting laser beams from the well positioned laserdiodes are collimated and coupled using free-space optics. The beam ormultiple laser beams are then funneled into a remotely positioned lightguide such as a fiber. Such a free-space configuration keeps the fibercoupling far from the laser diode chips.

FIG. 14 is an example of a free-space mirror based laser combiner.Individual laser beams are first collimated through free-space opticssuch as fast axis collimating (FAC) and slow axis collimating (SAC)lenses. Next the collimated laser beams are incident on turning mirrorsto change the direction of the laser beams by 90 degrees. This is donefor an array of laser diode beams which are combined into one singlebeam and then coupled into the light guide such as a fiber.

FIG. 15 is an example of enclosed free space laser module. A compactplug-and-play design provides a lot of flexibilities and ease of use.

FIG. 16 illustrates the strong lifetime dependence on laser couplingschemes. By adopting a free-space coupling (dashed line) approach toavoid direct fiber coupling (solid line), the degradation rate isstrongly suppressed to enable less than 20% degradation over 500 hrs ofoperation with output powers of over 5 W, over 10 W, over 30 W, or over60 W.

FIG. 17 is a simplified illustration of module form factor according toan embodiment of the present invention. As shown, the illustration ishow optical modules comprised of laser diode chips can providedrastically reduced form factors and thicknesses than conventional lampbased light sources and even laser diodes based on TO-can arrays. Suchreduction in thickness can enable smaller, more compact form factor CEproducts such as display projectors. The smaller form factor is anunexpected result of our integration. Further details of the presentsystem can be found throughout the present specification.

In an alternative embodiment of this invention, nonpolar or semipolarGaN-based laser diodes are employed in the module. Due to thealternative facet cleavage plane in such lasers based onnonpolar/semipolar orientations, and a waveguide design possibility thatdoes not include AlGaN cladding layers, such laser diodes could becompatible with direct fiber coupling without the rapid degradationdemonstrated for conventional c-plane devices.

In an alternative embodiment, the present invention provides an opticalmodule device combining the emissions of N laser beams, where N isgreater than 1. The method of optical combining includes free-spaceoptics to create one or more free space optical beams. The opticalemission comprises a blue emission in the 415 nm to 485 nm wavelengthrange and/or a green emission in the 500 nm to 560 nm wavelength range.The optical module device comprised to operate with over 5 W, over 20 W,or over 50 W. The optical module device is characterized by an opticaloutput power degradation of less than 20% in 500 hours when operated ata constant input current.

In certain embodiments, optical modules provided by the presentdisclosure comprise a plurality of laser diode devices numbered from 1through N overlying the support member, each of the plurality of laserdiode devices configured to emit a laser beam. The laser diode devicesmay include devices that emit in the violet region (390-430 nm), theblue region (430 nm to 490 nm), the green region (490 nm to 560 nm), theyellow region (560 nm to 600 nm), or in the red region (625 nm to 670nm) of the electromagnetic spectrum. An optical module may include acombination of laser diode devices emitting in different parts of theelectromagnetic spectrum In certain embodiments, the combination oflaser diodes is selected to produce a combined output radiation having adesired wavelength distribution. In certain embodiments, the combinedoutput can be a white light output. The laser diode devices may be basedon different semiconductor technology such gallium and nitrogencontaining devices or AlInGa although other suitable technologies may beemployed. In certain embodiments, at least some of the plurality oflaser diode devices comprise gallium and nitrogen containing laser diodedevices configured to emit a laser beam characterized by emissionselected from blue emission with a wavelength ranging from 415 nm to 485nm, green emission with a wavelength ranging from 500 nm to 560 nm, anda combination thereof. In certain embodiments at least some of theplurality of laser diode devices comprise AlInGaP laser diode deviceconfigured to emit a laser beam characterized by red emission with awavelength ranging from 625 nm to 670 nm.

In a specific embodiment, the package can be used in a variety ofapplications. The applications include power scaling (modularpossibility), spectral broadening (select lasers with slight wavelengthshift for broader spectral characteristics). The application can alsoinclude multicolor monolithic integration such as blue-blue, blue-green,RGB (Red-Blue-Green), and others.

In a specific embodiment, the present laser device can be configured ona variety of packages. As an example, the packages include TO9 Can, TO56Can, flat package(s), CS-Mount, G-Mount, C-Mount, micro-channel cooledpackage(s), and others. In other examples, the multiple laserconfiguration can have an operating power of 1.5 Watts, 3, Watts, 6Watts, 10 Watts, and greater. In an example, the present optical device,including multiple emitters, are free from any optical combiners, whichlead to inefficiencies. In other examples, optical combiners may beincluded and configured with the multiple emitter devices. Additionally,the plurality of laser devices (i.e., emitters) may be an array of laserdevice configured on non-polar oriented GaN or semi-polar oriented GaNor any combination of these, among others.

As used herein, the term GaN substrate is associated with GroupIII-nitride based materials including GaN, InGaN, AlGaN, or other GroupIII containing alloys or compositions that are used as startingmaterials. Such starting materials include polar GaN substrates (i.e.,substrate where the largest area surface is nominally an (h k 1) planewherein h=k=0, and 1 is non-zero), non-polar GaN substrates (i.e.,substrate material where the largest area surface is oriented at anangle ranging from about 80-100 degrees from the polar orientationdescribed above towards an (h k 1) plane wherein 1=0, and at least oneof h and k is non-zero) or semi-polar GaN substrates (i.e., substratematerial where the largest area surface is oriented at an angle rangingfrom about +0.1 to 80 degrees or 110-179.9 degrees from the polarorientation described above towards an (h k 1) plane wherein 1=0, and atleast one of h and k is non-zero). Of course, there can be othervariations, modifications, and alternatives.

In other examples, the present device is operable in an environmentcomprising at least 150,000 ppm oxygen gas. The laser device issubstantially free from AlGaN or InAlGaN claddings. The laser device issubstantially free from p-type AlGaN or p-type InAlGaN claddings. Eachof the emitter comprises a front facet and a rear facet, the front facetbeing substantially free from coatings. Each of the emitter comprises afront facet and a rear facet, the rear facet comprising a reflectivecoating. In other examples, the device also has a micro-channel coolerthermally coupled to the substrate. The device also has a submountcharacterized by a coefficient of thermal expansion (CTE) associatedwith the substrate and a heat sink. The submount coupled to thesubstrate, the submount comprises aluminum nitride material, BeO,diamond, composite diamond, or combinations In a specific embodiment,the substrate is glued onto a submount, the submount being characterizedby a heat conductivity of at least 200 W/(mk). The substrate comprisesone or more cladding regions. The one or more optical members comprise afast-axis collimation lens. The laser device is characterized by aspectral width of at least 4 nm. In a specific example, the number N ofemitters can range between 3 and 15, 15 and 30, 30 and 50, and can begreater than 50. In other examples, each of the N emitters produces anaverage output power of 25 to 50 mW, produces an average output power of50 to 100 mW, produces an average output power of 100 to 250 mW,produces an average output power of 250 to 500 mW, or produces anaverage output power of 500 to 1000 mW. In a specific example, each ofthe N emitters produces an average output power greater than 1 W. In anexample, each of the N emitters is separated by 3 μm to 15 μm from oneanother or separated by 15 μm to 75 μm from one another or separated by75 μm to 150 μm from one another or separated by 150 μm to 300 μm fromone another.

In yet an alternative specific embodiment, the present inventionprovides an optical device, e.g., laser. The device includes a galliumand nitrogen containing material having a surface region, which ischaracterized by a semipolar surface orientation within 5 degrees of oneof the following (10-11), (10-1-1), (20-21), (20-2-1), (30-31),(30-3-1), (40-41), or (40-4-1). The device also has a first waveguideregion configured in a first direction, which is a projection of ac-direction overlying the surface region of the gallium and nitrogencontaining material in a specific embodiment. The device also has asecond waveguide region coupled to the first waveguide region and isconfigured in a second direction overlying the surface region of thegallium and nitrogen containing material. In a preferred embodiment, thesecond direction is different from the first direction and substantiallyparallel to the a-direction. In a preferred embodiment, the first andsecond waveguide regions are continuous, are formed as a singlecontinuous waveguide structure, and are formed together duringmanufacture of the waveguides. Of course, there can be other variations,modifications, and alternatives.

In an example, the apparatus has a support member comprised of a coppermaterial, an aluminum material, a silicon material, or combinationsthereof. In an example, a micro-channel cooler thermally is coupled tothe support member. In an example, a heat spreader is coupled betweenthe support member and the laser devices.

In an example, a phosphor material is provided within the moduleapparatus and in particular optically coupled to the laser beams. In anexample, the phosphor material optically interacts with the plurality oflaser beams. The phosphor material operates in a reflective mode, atransmissive mode, or combinations thereof, and the like. The phosphormaterial is positioned in the optical path coupled to an optical elementor a metal or other material. The phosphor material is thermally coupledto the support member along a continuous thermal gradient toward aselected portion of a heat sink region within a vicinity of the supportmember. The apparatus also has an optical coupling of the plurality oflaser beams to a phosphor material external to the module apparatus. Inan example, the plurality of laser beams is guided through an opticalfiber to couple to the phosphor material. The output beam isgeometrically configured to optimize the interaction with the phosphorssuch as improving the efficiency of a phosphor conversion process. In anexample, a phosphor material coupled with the plurality of laser beamsand combiner to cause output of a selected spatial pattern having amaximum width and a minimum width.

In an example, the apparatus has an electrical input interface isconfigured to couple radio frequency electrical inputs to the pluralityof laser devices. The electrical input interface is configured to couplelogic signals to the plurality of laser devices.

In an example, the apparatus has a submount member characterized by acoefficient of thermal expansion (CTE) associated with the supportmember and a heat sink. In an example, a submount member is coupling theN laser devices to the support member. The submount member is made of amaterial including at least one of aluminum nitride, BeO, diamond,composite diamond, or combinations thereof. The submount members areused to couple the N laser devices to the support member. In a example,a submount is glued to the support member. In an example, the submountis characterized by a heat conductivity of at least 200 W/(mk). In anexample, the laser devices are directly thermally coupled directly tothe support member. In an example, at least a portion of the N laserdevices are configured on either a non-polar or semipolar gallium andnitrogen containing oriented surface region.

In an example, the nonpolar or semipolar oriented surface region is asemipolar orientation characterized by the {20-21} or {20-2-1} plane. Alaser stripe region overlies the semipolar surface region; wherein thelaser stripe region is oriented in the projection of the c-direction. Inan example, the nonpolar or semipolar oriented surface region is anonpolar orientation characterized by m-plane and a laser stripe regionoverlies the nonpolar surface region; wherein the laser stripe region isoriented in the c-direction. In an example, the plurality of laser beamsare individually optically coupled into a plurality of optical fibers.The plurality of the optical fibers are optically coupled with eachother to combine the plurality of laser beams into at least one outputbeam. The output beam is coupled into an optical fiber. In an example,the output beam is characterized by a wide spectral width of at least 4nm; wherein N ranges between 3 and 50, and the output beam ischaracterized by a narrow spectral width of less than 4 nm; wherein Nranges between 3 and 50. In an example, each of the N emitters producesan average output power of 10 to 1000 mW. In an example, each of the Nemitters produces an average output power of 1 to 5 W. The opticalmodule apparatus is characterized by an output power of 10 W andgreater, 50 W and greater, or 100 W and greater or 200 W and greater orless, although there may be variations. In an example, a thermalimpedance of less than 2 degrees Celsius per watt of electrical inputpower is characterizing the thermal path from the laser device to a heatsink. In an example, a thermal impedance of less than 1 Degrees Celsiusper watt of electrical input power is characterizing the thermal pathfrom the laser device to a heat sink. In an example, an optical outputpower degradation of less than 20% in 2000 hours is provided when theoptical module apparatus is operated at a rated output power with aconstant input current at a base temperature of 25 degrees Celsius. Inan example, an optical output power degradation of less than 20% in 5000hours is provided when the optical module apparatus is operated at arated output power with a constant input current at a base temperatureof 25 degrees Celsius. Depending upon the embodiment, the height ischaracterized by less than 7 mm or the height is characterized by lessthan 4 mm or the height is characterized by less than 2 mm.

In certain embodiments, an optical module apparatus comprises a formfactor characterized by a length, a width, and a height; the heightcharacterized by a dimension of less than 11 mm and greater than 1 mm,the apparatus comprising: a support member; a plurality of laser diodedevices numbered from 1 through N overlying the support member, each ofthe plurality of laser diode devices configured to emit a laser beam;wherein at least some of the plurality of laser diode devices comprisegallium and nitrogen containing laser diode devices configured to emit alaser beam characterized by emission selected from blue emission with awavelength ranging from 415 nm to 485 nm, green emission with awavelength ranging from 500 nm to 560 nm, and a combination thereof; andwherein N is greater than 1; a free space with a non-guidedcharacteristic capable of transmitting the laser beams from each of theplurality of laser diode devices; and a combiner configured to receivethe laser beams from each of the plurality of gallium and nitrogencontaining laser diode devices, and to provide an output beamcharacterized by a selected wavelength range, a selected spectral width,a selected power, and a selected spatial configuration, wherein: thesupport member is configured to transport thermal energy from theplurality of laser diode devices to a heat sink; the combiner comprisesfree-space optics configured to create one or more free space opticalbeams; at least one of the laser beams is characterized by apolarization purity of greater than 60% and less than 100%; the outputbeam is characterized by an operating optical output power of at least 5W; a thermal path from the plurality of laser diode devices to the heatsink characterized by a thermal impedance of less than 4 degrees Celsiusper electrical watt of electrical input power characterizing; and theoptical module apparatus is characterized by an optical output powerdegradation of less than 20% in 500 hours when the optical moduleapparatus is operated within the optical output power with a constantinput current at a base temperature of 25 degrees Celsius.

In certain embodiments of an optical module apparatus, at least some ofthe plurality of laser diode devices comprise AlInGaP laser diode deviceconfigured to emit a laser beam characterized by red emission with awavelength ranging from 625 nm to 665 nm.

In certain embodiments, an optical module apparatus further comprises anelectrical input interface configured to couple electrical input powerto each of the plurality of laser diode devices.

In certain embodiments of an optical module apparatus, the output poweris from 5 W to 200 W.

In certain embodiments of an optical module apparatus, each of theplurality of laser diode devices is operable in an environmentcomprising at least 150,000 ppm oxygen gas; wherein each of theplurality of laser diode devices is substantially free from efficiencydegradation over a time period from the oxygen gas.

In certain embodiments of an optical module apparatus, the supportmember comprises a material selected from copper, aluminum, silicon, anda combination of any of the foregoing.

In certain embodiments, an optical module apparatus further comprises amicro-channel cooler thermally coupled to the support member.

In certain embodiments, an optical module apparatus further comprises aheat spreader coupled between the support member and the plurality oflaser devices.

In certain embodiments, an optical module apparatus further comprises aphosphor material optically coupled to the output beam.

In certain embodiments of an optical module apparatus, a phosphormaterial is configured to operate in a mode selected from a reflectivemode, a transmissive mode, and a combination of a reflective mode and atransmissive mode.

In certain embodiments of an optical module apparatus, a phosphormaterial is coupled to an optical element or to a metal.

In certain embodiments of an optical module apparatus, a phosphormaterial is thermally coupled to the support member along a continuousthermal gradient toward a selected portion of a heat sink region withina vicinity of the support member.

In certain embodiments, an optical module apparatus further comprises anoptical coupler configured to optically couple the plurality of laserbeams to a phosphor material external to the module apparatus.

In certain embodiments of an optical module apparatus, an opticalcoupler comprises one or more optical fibers.

In certain embodiments of an optical module apparatus, the output beamis geometrically configured to optimize an interaction with a phosphormaterial from a first efficiency to a second efficiency.

In certain embodiments, an optical module apparatus further comprises aphosphor material coupled with the laser beams; and wherein the combineris configured to provide an output beam characterized by a selectedspatial pattern having a maximum width and a minimum width.

In certain embodiments of an optical module apparatus, an electricalinput interface is configured to couple radio frequency electricalinputs to the plurality of laser diode devices.

In certain embodiments of an optical module apparatus, an electricalinput interface is configured to couple logic signals to the pluralityof laser diode devices.

In certain embodiments, an optical module apparatus further comprises asubmount member characterized by a coefficient of thermal expansion(CTE) coupled to the support member and the heat sink.

In certain embodiments, an optical module apparatus further comprisesone or more submount members coupling the plurality of laser diodedevices to the support member.

In certain embodiments of an optical module apparatus, the one or moresubmount member comprises a material selected from aluminum nitride,BeO, diamond, composite diamond, and a combination of any of theforegoing.

In certain embodiments of an optical module apparatus, the one or moresubmount members is configured to couple the plurality of laser diodedevices to the support member.

In certain embodiments, an optical module apparatus further comprises asubmount attached to the support member, the submount beingcharacterized by a thermal conductivity of at least 200 W/(mk).

In certain embodiments of an optical module apparatus, the plurality oflaser diode devices are directly thermally coupled directly to thesupport member.

In certain embodiments of an optical module apparatus, at least aportion of the plurality of laser diode devices is overlies an orientsurface region selected from a non-polar gallium and nitrogen containingoriented surface region and a semipolar gallium and nitrogen containingoriented surface region.

In certain embodiments of an optical module apparatus, an orientedsurface region is a semipolar orientation characterized by the {20-21}or {20-2-1} plane; and a laser stripe region overlies the orientedsurface region; wherein the laser stripe region is oriented in theprojection of the c-direction.

In certain embodiments of an optical module apparatus, an orientedsurface region is a nonpolar orientation characterized by the m-plane;and a laser stripe region overlies the oriented surface region, whereinthe laser stripe region is oriented in the c-direction.

In certain embodiments of an optical module apparatus, free space opticscomprises a fast-axis collimation lens.

In certain embodiments, an optical module apparatus further comprises anoptical fiber, wherein the output beam is coupled into the opticalfiber.

In certain embodiments of an optical module apparatus, an output beam ischaracterized by a spectral width of at least 4 nm; and N ranges from 3to 50.

In certain embodiments of an optical module apparatus, an output beam ischaracterized by a spectral width of less than 4 nm; and N ranges from 3to 50.

In certain embodiments of an optical module apparatus, each of theplurality of laser diode devices emits a laser beam characterized by anaverage output power from 10 mW to 1000 mW.

In certain embodiments of an optical module apparatus, each of theplurality of laser diode devices emits a laser beam characterized by anaverage output power from 1 W to 5 W.

In certain embodiments of an optical module apparatus, an output poweris selected from 10 W and greater, 50 W and greater, and 100 W andgreater.

In certain embodiments of an optical module apparatus, a thermalimpedance is less than 2 degrees Celsius per watt of electrical inputpower.

In certain embodiments of an optical module apparatus, a thermalimpedance is less than 1 degrees Celsius per watt of electrical inputpower.

In certain embodiments of an optical module apparatus, the opticaloutput power degradation is less than 20% in 2,000 hours when theoptical module apparatus is operated within the output power with aconstant input current at a base temperature of 25 degrees Celsius.

In certain embodiments of an optical module apparatus, the opticaloutput power degradation is less than 20% in 5,000 hours when theoptical module apparatus is operated at within the output power with aconstant input current at a base temperature of 25 degrees Celsius.

In certain embodiments, an optical module apparatus comprising a formfactor characterized by a length, a width, and a height; the heightcharacterized by a dimension of less than 11 mm and greater than 1 mm,the apparatus comprising: a support member; a plurality of laser diodedevices numbered from 1 through N overlying the support member, each ofthe plurality of laser diode devices configured to emit a laser beam;wherein at least some of the plurality of laser diode devices comprisegallium and nitrogen containing laser diode devices configured to emit alaser beam characterized by emission selected from blue emission with awavelength ranging from 415 nm to 485 nm, green emission with awavelength ranging from 500 nm to 560 nm, and a combination thereof; andwherein N is greater than 1; a waveguiding member configured to transmitthe laser beams from the plurality of laser optical devices; and acombiner configured to receive laser beams from the plurality of laserdiode devices; and to provide an output beam characterized by a selectedwavelength range, a selected spectral width, a selected power, and aselected spatial configuration; wherein the support member is configuredto transport thermal energy from the plurality of laser diode devices toa heat sink; at least one of the laser beams is characterized by apolarization purity of greater than 60% and less than 100%; the outputbeam is characterized by an optical output power of at least 5 W; and athermal path from the laser device to a heat sink is characterized by athermal impedance of less than 4 degrees Celsius per electrical watt ofinput power.

In certain embodiments, an optical module apparatus comprising a formfactor characterized by a length, a width, and a height; the heightcharacterized by a dimension less than 11 mm and greater than 1 mm, theapparatus comprising: a support member; a plurality of laser diodedevices numbered from 1 through N overlying the support member, each ofthe plurality of laser diode devices configured to emit a laser beam;wherein at least some of the plurality of laser diode devices comprisinggallium and nitrogen containing laser diode devices characterized by anonpolar or semipolar oriented surface region and configured to emit alaser beam characterized by emission selected from blue emission with awavelength ranging from 415 nm to 485 nm, green emission with awavelength ranging from 500 nm to 560 nm, and a combination thereof; andwherein N is greater than 1; a laser stripe region overlying thenonpolar or semipolar surface region; wherein each laser stripe regionis oriented in a c-direction or a projection of a c-direction andcharacterized by a first end and a second end; and a combiner configuredto receive a plurality of laser beams of N incoming laser beams; thecombiner functioning to cause an output beam with a selected wavelengthrange, spectral width, power, and spatial configuration, where N isgreater than 1; wherein the support member is configured to transportthermal energy from the plurality of laser diode devices to a heat sink;at least one of the laser beams is characterized by a polarizationpurity of greater than 60% and less than 100%; the output beam ischaracterized by a predetermined rated operating optical output powerrange of at least 5 W; and a thermal path from the laser device to aheat sink is characterized by a thermal impedance of less than 4 degreesCelsius per electrical watt of input power.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. Therefore, the above description and illustrations should not betaken as limiting the scope of the present invention which is defined bythe appended claims.

What is claimed is:
 1. An optical module apparatus comprising: aplurality of ceramic support members; a plurality of laser diodes eachcoupled to one of the plurality of ceramic support members to form aplurality of laser diode chips, each of the plurality of laser diodechips having a single laser diode configured to emit a laser beam;wherein at least one of the plurality of laser diode chips comprises agallium and nitrogen containing laser diode device configured to emit alaser beam characterized by emission selected from violet emission witha wavelength ranging from 395 nm to 425 nm, blue emission with awavelength ranging from 415 nm to 485 nm, or green emission with awavelength ranging from 500 nm to 560 nm; one or more optical devicesconfigured to receive laser beams from the plurality of laser diodechips, and to combine or collimate the laser beams to provide an outputbeam characterized by a selected wavelength range, a selected spectralwidth, a selected power, and a selected spatial configuration; and apower source electrically coupled to the plurality of laser diode chips;wherein: the plurality of ceramic support members are configured totransport thermal energy from the plurality of laser diode chips to aheat sink; the one or more optical devices comprise free-space opticsconfigured to create one or more free space optical beams; a thermalpath from each of the plurality of laser diode chips to the heat sink ischaracterized by a thermal impedance; and the optical module apparatusis characterized by an optical output power of at least 5 W.
 2. Theapparatus of claim 1, wherein at least one of the plurality of laserdiode chips comprises an AlInGaP laser diode device configured to emit alaser beam characterized by red emission with a wavelength ranging from625 nm to 665 nm; or wherein at least one of the plurality of laserdiode chips comprises a GaAs or AlGaAsP laser diode device configured toemit a laser beam characterized by an infrared emission, or acombination thereof.
 3. The apparatus of claim 1, further comprising anelectrical input interface configured to couple electrical input powerto the plurality of laser diode chips; and wherein the electrical inputinterface is configured to couple radio frequency electrical inputs tothe laser diode chips or wherein the electrical input interface isconfigured to couple logic signals to the laser diode chips.
 4. Theapparatus of claim 1, wherein the plurality of laser diode chips areoperable in an environment comprising at least 150,000 ppm oxygen gas;wherein each of the plurality of laser diode chips is substantially freefrom efficiency degradation over a time period from the oxygen gas. 5.The apparatus of claim 1, further comprising a combiner configured toprovide the output beam characterized by a selected spatial patternhaving a maximum width and a minimum width.
 6. The apparatus of claim 1,further comprising a plurality of submount members characterized by acoefficient of thermal expansion (CTE) each coupled to one of theplurality of ceramic support members and the heat sink, wherein theplurality of submount members couple the plurality of laser diode chipsto the plurality of ceramic support members.
 7. The apparatus of claim6, wherein each of the plurality of submount members comprises amaterial selected from aluminum nitride, silicon carbide, BeO, diamond,composite diamond, and a combination of any of the foregoing.
 8. Theapparatus of claim 1, further comprising a submount attached to theplurality of ceramic support members, the submount being characterizedby a thermal conductivity of at least 200 W/(mk); and wherein each ofthe plurality of laser diode chips are thermally coupled directly to oneof the plurality of ceramic support members.
 9. The apparatus of claim1, wherein the one or more optical devices comprise an optical fiber,wherein the output beam is coupled into the optical fiber.
 10. Theapparatus of claim 1, wherein the plurality of laser diode chips includeN laser diode chips and N ranges from 3 to
 50. 11. The apparatus ofclaim 1, wherein the output beam is characterized by an optical power of5 W and greater, 10 W and greater, 50 W and greater, 100 W and greater,or 200 W and greater.
 12. An optical module apparatus comprising: aplurality of ceramic support members; a plurality of laser diodes eachcoupled to one of the plurality of ceramic support members to form aplurality of laser diode chips; each of the plurality of laser diodechips having a single laser diode configured to emit a laser beam;wherein at least one of the laser diode chips comprises gallium andnitrogen and is configured to emit a laser beam characterized byemission selected from violet emission with a wavelength ranging from395 nm to 425 nm, blue emission with a wavelength ranging from 415 nm to485 nm, green emission with a wavelength ranging from 500 nm to 560 nm,and a combination thereof; one or more optical devices configured toreceive laser beams from the plurality of laser diode chips, and tocombine and/or collimate the laser beams; the laser beams characterizedby a selected wavelength range, a selected spectral width, a selectedpower, and a selected spatial configuration; wherein the one or moreoptical devices comprise free-space optics configured to create one ormore free space optical beams; an optical fiber configured to receivethe laser beams from the plurality of laser diode chips by opticalcoupling; and to provide an output beam characterized by a selectedwavelength range, a selected spectral width, a selected power, and aselected spatial configuration; wherein: the plurality of ceramicsupport members are configured to transport thermal energy from theplurality of laser diode chips to a heat sink; and the output beam ischaracterized by an optical output power of at least 5 W.
 13. Theapparatus of claim 12, wherein the free space optics provide opticalcoupling of the laser beams to the optical fiber and are selected fromone or more of a fast axis collimating (FAC) lens or a slow axiscollimating (SAC) lens.
 14. The apparatus of claim 12, wherein theoptical fiber is spaced from the plurality of laser diode chips bybetween about 0.2 mm to about 10 mm.
 15. The apparatus of claim 12,wherein the output beam is characterized by an optical power of 5 W andgreater, 10 W and greater, 50 W and greater, 100 W and greater, or 200 Wand greater.
 16. The apparatus of claim 12, wherein the optical fiberhas a dimension of between about 100 μm to about 800 μm.
 17. Theapparatus of claim 12, wherein at least one of the laser diode chipscomprises an AlInGaP laser diode device configured to emit a laser beamcharacterized by red emission with a wavelength ranging from 625 nm to665 nm; or wherein at least one of the laser diode chips comprises aGaAs or AlGaAsP laser diode device configured to emit a laser beamcharacterized by an infrared emission, or a combination thereof.
 18. Asystem comprising: an optical module apparatus; a package configured toenclose the optical module apparatus; and an application configured withthe optical module apparatus, the optical module apparatus comprising: aplurality of ceramic support members; a plurality of laser diodes eachcoupled to one of the plurality of ceramic support members to form aplurality of laser diode chips; each of the plurality of laser diodechips having a single laser diode configured to emit a laser beam;wherein at least one of the laser diode chips comprises a gallium andnitrogen containing laser diode device configured to emit a laser beamcharacterized by emission selected from violet emission with awavelength ranging from 395 nm to 425 nm, blue emission with awavelength ranging from 415 nm to 485 nm, or green emission with awavelength ranging from 500 nm to 560 nm; one or more optical devicesconfigured to receive laser beams from the plurality of laser diodechips, and to combine or collimate the laser beams to provide an outputbeam characterized by a selected wavelength range, a selected spectralwidth, a selected power, and a selected spatial configuration; and apower source electrically coupled to the plurality of laser diode chips;wherein: the plurality of ceramic support members are configured totransport thermal energy from the plurality of laser diode chips to aheat sink; the one or more optical devices comprise free-space opticsconfigured to create one or more free space optical beams; a thermalpath from each of the plurality of laser diode chips to the heat sink ischaracterized by a thermal impedance; and the optical module apparatusis characterized by an optical output power of 5 W or greater.
 19. Asystem comprising: an optical module apparatus; a package configured toenclose the optical module apparatus; and an application configured withthe optical module apparatus, the optical module apparatus comprising: aplurality of ceramic support members; a plurality of laser diodes eachcoupled to one of the plurality of ceramic support members to form aplurality of laser diode chips; each of the plurality of laser diodechips having a single laser diode; each of the plurality of laser diodechips overlying one of the plurality of ceramic support members, each ofthe laser diode chips configured to emit a laser beam; wherein at leastone of the laser diode chips comprises gallium and nitrogen and isconfigured to emit a laser beam characterized by emission selected fromviolet emission with a wavelength ranging from 395 nm to 425 nm, blueemission with a wavelength ranging from 415 nm to 485 nm, green emissionwith a wavelength ranging from 500 nm to 560 nm, and a combinationthereof; one or more optical devices configured to receive laser beamsfrom the plurality of laser diode chips, and to combine and/or collimatethe laser beams; the laser beams characterized by a selected wavelengthrange, a selected spectral width, a selected power, and a selectedspatial configuration; wherein the one or more optical devices comprisefree-space optics configured to create one or more free space opticalbeams; an optical fiber configured to receive the laser beams from theplurality of laser diode chips by optical coupling; and to provide anoutput beam characterized by a selected wavelength range, a selectedspectral width, a selected power, and a selected spatial configuration;wherein: the plurality of ceramic support members are configured totransport thermal energy from the plurality of laser diode chips to aheat sink; and the output beam is characterized by an optical outputpower of at least 5 W.